According to current practice, electrical circuitry assemblies including an electrical connection with a circuit, preferably a flexible circuit, are established by direct access to the conductive layer of said circuit, preferably a copper layer, from both sides, which is also known as “back-bared” construction. Thereby, the material forming said conductive layer, e.g. the copper layer, of said circuit is exposed from both sides at a location where an electrical contact to an electrically conductive metal plate shall be established. In particular, electrical connections of a flexible circuit with another electrically conductive member are exemplarily used in the field of battery cell interconnections and battery cell management systems or the like. Consequently, a failure of such an electrical connection usually leads to an irreparable failure of the whole product due to miniaturization of electrical circuits.
However, this known manufacturing procedure and electrical circuitry assembly entails several disadvantages. First, it leads to a structure of the electrical connection which necessitates e.g. the application of a thicker and more expensive copper foil or the application of any kind of mechanical strain relief solution in order to achieve a minimum strength of the electrical connection. Second, the conductive or copper layer of the flexible circuit is exposed to the environment on two sides and further process steps are necessary to provide an adequate protection for the exposed part of the conductive or copper circuit layer. Third, flexible circuits are used in terms of providing flexibility and subsequently a movement of such flexible electrical conductor may cause the breaking of the electrical connection. Finally, there is a need for providing a simplified and reliable construction of electrical interconnections, in particular for electrical circuitry assemblies between a relatively stiff metal plate part and a flexible circuit.